Sandblasting

Although sand is most commonly used as an abrasive, other materials can also be encountered in practice: for instance, hardwood sawdust, soft rock grit, crushed seeds or nutshells, steel shot, silica sand, corundum, steel grit, cast iron grit, slag, or anything with similar properties (sometimes abrasives dissolved in liquid are also used), simply whatever the company has at hand.

Sandblasting is widely used on knives.

What is the history of sandblasting?

The entire process of sandblasting is quite old— already in 1870, it was patented by Benjamin Chew Tilghman (USA patent 104 408). And it should be noted that even back then, it was a significantly unhealthy process and today protective equipment is absolutely necessary because the working person was continually exposed to silica sand, so if someone systematically inhaled it, it was only a matter of time before dying from severe and fatal lung damage today known as silicosis.

What is sandblasting used for today and in the past?

Perhaps the most common practical use of sandblasting today is in the engineering field, where it is used to clean castings before further surface treatment (such as regular painting). Sandblasting perfectly removes any traces of machining. Today, the most used method is probably air pressure blasting, where sand particles are carried by air, but mechanical blasting also has its place, where the abrasive material is thrown by fast-rotating blades.

Today, however, sandblasting is also often used in construction for finer processing of stone, concrete, or masonry. It is also popular in cities, where it is one of the key methods to remove various paints, sprays (graffiti), and any similar potential contamination from walls, facades, columns, and other surfaces.

Sandblasting also has its place in art, where it is used as an interesting and effective technique for unusual surface treatments. These are various paperweights, mugs, mirrors, etc. It is also possible to sandblast items made of ceramics and wood. And today, advertising sandblasting of gift items through a form giving them a specific shape is very popular.

What national standards apply to sandblasting here?

"Basic degrees of surface cleaning according to ČSN ISO 8501-1 correspond to DIN 55928, respectively the Swedish standard SIS 055900:

• Sa 3 - Blasting cleaning to pure metal. All visible traces of scale, rust, and other impurities are removed. The surface has a uniform metallic appearance.
• Sa 2.5 - Blasting cleaning to near pure metal. Visible scales, rust, and other impurities are removed. Any remaining traces of contamination will only appear as light stains in the form of spots or stripes.
• Sa 2 - Blasting cleaning. Visible non-adherent scales, rust, and other impurities are removed. All residues must be firmly adhered to the substrate.
• St 2 - Manual and power tool cleaning. Poorly adherent scales, rust, and other impurities are removed.
• St 3 - Manual and power tool cleaning. Similar to St2, but the surface must exhibit a distinct metallic sheen."